Source : http://underpop.online.fr/l/linux/en/centos/s2-sysconfig-nfs.htm
NFS requires portmap/rcpbind, which dynamically assigns ports for RPC services. This causes problems for configuring firewall rules. To overcome this problem, use the /etc/sysconfig/nfs file to control which ports the required RPC services run on.
Deprecate /etc/sysconfig/nfs and only use /etc/nfs.conf to configure NFS daemons
The /etc/sysconfig/nfs may not exist by default on all systems. If it does not exist, create it and add the following variables (alternatively, if the file exists, un-comment and change the default entries as required):
MOUNTD_PORT=x
control which TCP and UDP port mountd (rpc.mountd) uses. Replace x with an unused port number.
STATD_PORT=x
control which TCP and UDP port status (rpc.statd) uses. Replace x with an unused port number.
LOCKD_TCPPORT=x
control which TCP port nlockmgr (rpc.lockd) uses. Replace x with an unused port number.
LOCKD_UDPPORT=x
control which UDP port nlockmgr (rpc.lockd) uses. Replace x with an unused port number.
If NFS fails to start, check /var/log/messages. Normally, NFS will fail to start if you specify a port number that is already in use. After editing /etc/sysconfig/nfs restart the NFS service by running the service nfs restart command. Run the rpcinfo -p command to confirm the changes.
To configure a firewall to allow NFS:
MOUNTD_PORT=“x”STATD_PORT=“x”LOCKD_TCPPORT=“x”LOCKD_UDPPORT=“x”